I have MKVs and it has h.264 and aac which is perfect for iOS devices. so I don't want to re-encode it. just want to change the container to MP4.
It's and easy task for ffmpeg or MP4box but I want soft subtitles in the MP4 that iOS can recognize.

ffmpeg could only create hard burn subtitles.
MP4box was able to add subtitle track but only VLC able to load it. iOS can't play the sub which is added by MP4box.

MediaCoder seenms like a GUI of those tools so I still want to ask. is that possible to create a MP4 with subtitles that iOS iphone ipod can play?

I have app can do this but all of them are MAC apps. like subler and MP4Tools, handbreak could do this too but don't support copy video. I don't want to re-encode!